Condensation/Mould Prevention

Reduce condensation at source, use a extractor fan when cooking, use saucepan lids when simmering, open a window when showering (extractor fan on), dry clothes outside, inside use dehumidifier. Got a dishwasher?.. let it cool before opening it after a wash.

If you want to stay warm inside your home it's difficult to eliminate condensation altogether in cold snaps. As warm air holds more moisture than cold air as soon as it its a cool surface water will condense on it. All you can do is try to minimise it the best you can using the methods mentioned in many of the posts above. A good tip I read was to squeegee you shower cubical down after use, more water then goes down the drain rather than evaporating into the air.

Look at positive input ventilation systems. I'm sure nuaire do a version for flats

ebac ones have a smart function, they switch themselves off if humidity gets to a certain level saving energy or you can set them to max/min settings fan high low..

How do you dry your clothes after you have washed them?

Is there an extractor fan in each bathroom/shower room that continues to run for a while after you have finished in the room?

Do you open the kitchen window a bit when you are boiling veg/spaghetti etc?

You need to leave the vents in your windows open or certain windows ajar.
Condensation comes from moisture in the air from you breathing or hot air touching cold walls and surfaces. If you don't have an airflow to the outside the moisture gathers indoors and lies on surfaces causing mould.

Is the radiator under the window? When was the flat built?

Moisture traps, dehumidifier and ventilation will all help together.

I'm considering a dehumidifier. No idea where to locate it to deal with condensation upstairs and downstairs; does it stay on all night etc etc

1 - Karcher to get rid of the condensation every morning
2 - Open windows just a bit during the day (especially bathroom but any room that has a lot of condensation)
3 - Dehumidifer will help - no doubt

My daughter's bedroom has similar issues - doing the above the past few weeks has started to have an effect, less condensation each morning.

There's more moisture in the air inside the house, and excessive condensation happens when there's not enough exchange of air between the inside and outside to equalise fast enough.

It doesn't take much airflow for normal moisture build up so if you've got vents open for a while each day then it's worth investigating for other sources of moisture. Building issues can cause this. Leaking roofs, overflowing gutters, foundation problems, cracked pipes. It's worth talking to people in the other flats in the building to see if they have any issues, especially if you're in the middle and not top or bottom.

You can suck the moisture out of the air using a dehumidifier but this is just a patch so it's best to do some investigating first as if there is an issue then it's usually cheaper to fix it early rather than letting it get worse.

this happens if there is not enough ventilation for the air to escape but it is blooming cold so it isn't easy to open the window and let the air out! a dehumidifier will certainly help and turning the heating on so that the flat is warm all the time will help, but again that is costly.

This is a good video explaining the situation and there are many more like it.

Charlie Diyte (edited)

Sadly best option is to leave a window slightly ajar/open, kitchen or bathroom being your best bet....even if it's -6c like it was where I live last night lol. Weirdly the flat doesn't cool too much and helps prevent the condensation or completely prevent it.

We don't put the CH on until late afternoon for a few hours. There is an energy crisis going on so the idea of stopping the condensation by having the heating on would cost 1000s - our utility bills are already massive despite living frugally with low energy bulbs, using a laptop rather than a desktop for work etc.

As an aside, we've got three of the passive dehumidiers whcih suck up a lot of water but barely make any different if a window isn't open. I won't be buying any more of them. Have considered a powered Meaco dehumifier but obviously size and energy consumption has to also be considered

Our flat is 130 y/o, 160 sq m with 3.5m hgih ceilings but doesn't matter if it's a new build, like we had before which also had awful condensation if a window wasn't ajar somewhere in the flat during the winter months.

I've been using tubs filled with de-icer salt on my window sill it's made a huge difference to my windows. I was having to use my karcher every morning but not since I started using the de-icer salt.